1. Field of the Invention
This invention relates generally to an apparatus for treating chondromalacia, and more particularly to an apparatus that treats chondromalacia with minimal disruption of the cartilage bed of the knee.
2. Description of Related Art
The normal function of joints in humans depends on the distribution of relatively large forces across the body surfaces. In diarthrodial joints the magnitude of the joint forces reaches levels four to seven times body weight. These forces applied to joints are dispersed by articular cartilage. Cartilage function occurs via a highly organized extracellular matrix maintaining a fixed charge density and possessing a high affinity for water.
Normal articular cartilage consists of an assembly of large and small proteoglycans, collagens, hyaluronic acid and glycoproteins. These matrix macromolecules originate from chondrocytes localized in a nonrandom pattern through the cartilage matrix. In normal joints, chondrocytes do not proliferate; dividing chondrocytes indicate a change in cartilage homeostasis, either as regeneration or attempted repair.
Chondromalacia occurs when cartilage beds in joints become worn and strands of cartilage distended away from their respective cartilage beds and extend into the joint capsule. The cartilage surface becomes visibly disrupted, fissured and fibrillated. This has deterious effects on the mechanical properties of articular cartilage. This distension has been associated with knee pain. Treatment to date has included surgical intervention. In one arthroscopic procedure, a shaver is introduced through an arthroscope and is used to remove the strands of disrupted and fibrillated cartilage. However, this treatment can disrupt and remove part of the normal cartilage bed and does not restore a smooth surface nor the mechanical function.
It would be desirable to provide a method and apparatus treating fibrillated cartilage joint surfaces or irregular cartilage joint surfaces by delivering sufficient thermal energy to reduce a level of fibrillation or irregularity of the fibrillated cartilage joint surface or the irregular cartilage joint surface. It would also be desirable to modify the fibrillated cartilage surface to a smooth surface. It would be further desirable to treat chondromalacia by reducing a level of fibrillation or irregularity of a fibrillated or irregular cartilage joint surface.